By Dr. Tijana Ivancevic and Prof. Leon Lukman

A new tennis shot is emerging from the field of sports science. It is a real weapon, which can generate the ball speed similar to the first serve. It is a natural movement, which can be learned by any kid that has ever thrown a ball or a stone. It has both biomechanics and neurophysiology in its foundation. It is called Power High-Forehand (PHF). Power means force times velocity: it gives the maximum power. High means that it is designed for high balls, from the waist up. And it is a superior alternative to the current forehand. Its aim is to generate maximal possible racket-head speed, and yet it allows for a moderate amount of topspin. The PHF should be executed as follows .

Let’s assume that you start from the base-line (as usual). You play your normal game, but as soon as you anticipate a high ball coming at a waist/chest level (or higher) while passing over the service-line, you don’t wait behind the base-line for the ball to come to you, but immediately sprint as fast as you can towards the service-line and a little-bit left from the ball, while at the same time leaving the racket-head behind your right shoulder (preparing for the shot). When you get close to the ball, you make sure that you stop about half-a-meter left from the ball’s direction, with the left foot forward. This automatically forms the left closed stance (as if you want to execute the right-hand karate gyaku-zuki punch), with the racket-head far behind your right shoulder. Then you are ready to intercept the ball and execute the winning shot.

Once you are in the proper left stance (as explained above), the PHF-shot is properly executed as a full biomechanical chain, based on the sequence of stretch reflexes in all included muscular actuators, one by one as a cascade. It is represented by the following sequence of individual joint movements:

Sharp right knee extension (with the right foot/heel firmly on the ground), while stretching the right hip muscles (gluteus medius and maximus);

Sharp right hip forward rotation, while leaving the right shoulder back and thus stretching the right waist muscles (external and internal abdominal muscles);

Sharp medial torso rotation, while leaving the arm back and thus stretching the pectoral and deltoid muscles;

Sharp right elbow movement forward (by shoulder abduction), while leaving the racket-head back, and thus stretching the right triceps;

Sharp right elbow extension, while still leaving the racket-head back, and thus stretching the right wrist flexor muscles; and

Sharp right wrist flexion, with simultaneous pronation to generate some amount of topspin for ball control.

This, in a nutshell, is how the PHF-shot should be executed.

Now, how do you know that you are really executing the proper PHF-shot?

The first criterion is this: it cannot be done slowly. It can be performed moderately fast or extremely fast, more tensed or more relaxed, but never slow. This is the first criterion for any stretch-reflex based movement.
Here is a simple familiar example: teaching long jump to small kids. You have a short run-up and then you jump. You can run slowly, but you simply cannot jump slowly. Why? Because a single-legged jump (from running) is based on the stretch reflex in all leg extensor muscles (soleus, quadriceps and gluteus). No stretch reflex, no jump – as simple as that.

It is the same with all naturally fast movements, including the PHF: it can be done in a more tensed or a more relaxed way, but it cannot be executed slowly. The very nature of stretch-reflex based movements is its inherent speed (as well as strength). It is not meant for slow and/or weak movements.
Biomechanical term for the whip–like movement is the kinetic chain: the sequential flow of energy and momentum from bigger segments to smaller ones. Tennis requires sequenced activation of muscles and movement of bones and joints to achieve the motions, positions, and velocities seen in a player. This sequencing is known as the kinetic chain. Kinetic energy and momentum, as well as muscular power, are developed from the legs, hips and trunk muscles and transferred to the arm muscles. This allows the energy, momentum and power to be transferred efficiently to the hands, moving the racquet-head with maximum speed to the ball.

Research evidence suggests that a proximal-to- distal firing pattern is the most effective for increasing the racket-head speed in the serve, forehand and backhand. In such a sequencing pattern, the stronger more heavily muscled proximal (close to the torso) joints should become activated before the weaker but faster distal joints. This firing pattern has proven the most efficient due to the fact that it takes advantage of each joints’ linear and angular momentum generating characteristics. It suggests that power (that is, both speed and strength combined) for the serve, forehand and backhand is primarily generated with: (i) leg extension, (ii) hip rotation, and (iii) trunk rotation (and/or flexion) – before the actual arm’s action. The actions of these proximal joints account for more than 50% of the total forces in the serve, forehand and backhand.

Here, we promote the interceptive tennis tactics, as a superior alternative to the current static tennis in which both players most of the time just wait behind the base line for the ball to bounce from the ground and come to them. In this power interceptive tennis, the players do not wait for the ball to bounce, but rather aggressively intercept as soon as the ball passes the service line and hit it in the air. This significantly shortens the time for opponent to react. If executed properly, this shot has the same effect as the smash. However, while an opportunity for a smash usually happens only about once in a tennis match, if you develop proper interceptive skills you will realise that most of the balls coming over the net can be intercepted – with the winner. This is both tactical and psychological basis for the future tennis game. Proper interception is heavily based on the anticipation of the ball coming (both its direction and height – while passing over the service-line) . This aggressive interceptive psychology will shape the minds of the future tennis champions.

The stretch–reflex is the secret behind both speed and strength in sport. It is the quickest reflex in the human body (about 5 milliseconds) , in which the reflex arc is a closed loop: both the receptor and the effector are in the same skeletal muscle. The stretch–reflex causes a stretched muscle to contract stronger and faster, and at the same time inhibits the antagonist muscle from contracting (that is, slowing the movement). Because this is an involuntary reflex response, the rate of contraction is significantly (several times) faster and more powerful than a voluntary muscular contraction. In fact, the faster the muscle is stretched eccentrically, the greater the speed and force will be on the following concentric contraction. The key point for the future tennis is that it is vital to have a relaxed, loose body before hitting the ball in order to achieve an effective shot. The aim of the aggressive high forehand: AHF is to generate a maximum speed at which the racket-head would work in unison with the serve to generate a faster serve or shot overall.

A detailed and demonstrated explanation of a tennis weapon of the future, the aggressive high forehand, based on the stretch reflex, is given in the Springer book Paradigm Shift for Future Tennis.

The whole kinetic chain is: knee then hip then shoulder then elbow then wrist, with small delays between all the links. So, nothing goes simultaneously. Then you have all three: the chain, the stretch reflex and the whip-like movement. Apparently, tennis coaches call this chain/reflex approach “a theory”, while in athletics this is both the basic knowledge and an everyday practice. If Zelezny’s javelin throw is adapted to tennis serve and high forehand, they would both go up to 300 km/h and volleys would become obsolete and opponents would try to run away.

A shining example of how knowledge could be powerful is biomechanics of Vladimir Zatsiorsky, who has been acknowledged by over 90 Olympic champions in various sports.

Djokovic’s skills are best seen through the way he returns the ball on very wide shots (primarily: wide serves and ground strokes and backhand side shots in particular). As you can see: he sprints from his starting position at the middle of the baseline and slides his legs wide apart in order to reach the ball just as it is about to pass him (the widening of the stance is a style similarly used by tennis players who work on clay courts). Afterwards, rather than moving to make a stretched, double-handed backhand (which, in this case, would be too short a move for such a wide shot), he stretches his right hand outwards for a single-handed backhand and spins his body away from the court. By doing so he turns his back to face his opponent while his eyes remain on the ball. He does this to achieve a longer reach as he returns the shot by flicking the ball back on the other side of the court. Afterwards, he spins to the left quickly to face the court again and prepare for the next forehand shot.